Because of the excellent mechanical and thermal properties imbued to polymers of benzimidazole (see Encycl. of Polymer. Sci. and Engineering, Second Edition, Vol. 7, pp. 639-665, 1987 and Encycl. of Polymer Sci. and Engineering, Second Edition, Vol. 11, pp. 572-601, 1988), it is desirable to incorporate this nucleus into these "Reissert compound polymers". However, only two examples of a Reissert-type compound from benzimidazole have been reported, and they were formed from chloroformates and not from acid chlorides (see J. Heterocyclic Chem. 1987, 24, 1349-1351). Attempts to use acid chlorides led to destruction of the benzimidazole nucleus (see J. Chem. Soc., Chem. Comm., 1984, 1245-1246). Thus, for the production of benzimidazole polymers by Reissert chemistry difunctionality was required as well as a means of producing Reissert compound moieties from acid chlorides. This invention relates to the discovery of methods for producing difunctional benzimidazole Reissert compounds.